In the automobile part industry, the requirements for the appearance and performance of wheels as special parts, especially for the performance of spokes, are extremely stringent. In aluminum wheel enterprises, the performance of the spokes is usually improved by strengthening side mold cooling. This method is repeatedly used and effective in air-cooled molds. However, counterproductive effects often occur in water-cooled molds, and the root cause is the unreasonable design of the side mold water-cooling structure. FIGS. 1A-1B show schematic diagrams of a side mold water-cooling structure of a conventional water-cooled mold. The cooling water channel is opened downward, and the insulating groove is only opened to the window zone and is a blind hole insulating groove, which inevitably causes the side mold cooling effect to be stronger at the lower part than at the upper part, so that the shrinkage porosity easily occurs at the roots of the spokes when the side mold cooling opening time is slightly long or the flow rate is slightly large. The present disclosure will provide an improved side mold water-cooling structure to solve the current problems.